Milling machines, both the vertical type and horizontal type, are used for machining workpieces according to a large number of complex operations, such as slotting, planing, drilling, rabbeting, routing, etc. However, the conventional milling machine is not capable of making certain types of cuts, such as keyways and slots having sharp interior corners. Therefore when these types of cuts are required to be made, a conventional milling machine is generally used to cut the workpiece in an unfinished form, and then another working operation is performed on the workpiece, such as a laser machining or a chemical etching operation, in order to finish the workpiece with the desired sharp internal corners.